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3DS Max Full Head Mapping

3DS Max Full Head Mapping

The real challenge is to get a head mapped all the way
around.Cylindrical mapping helps us
quite a bit, but there is still that problem with how to generate the
textures.On the source
code page there is a plug in
for 3D Studio Max®
that will help you generate a single unfolded texture.It may seem like it isn’t too difficult to
do, but after this explanation you would probably agree that this was one of
the most difficult pieces of code to write.What we want
to accomplish is the ability to map to orthogonal view pictures into one
texture map.

Getting Started

For the plug-in to work we need to set up some mapping for
the head that was created.Create a
Multi/Sub-Object in the material editor of 3D Studio Max®.Set the number of sub-objects to four by
clicking on the set number.Next create
four sub-materials that have textures.The first one should have its material ID set to 1.This one will be used for the cylindrical map
that will be applied in the final stage.The plug-in used the Material IDS to figure out which side of the head
the 2D texture is being applied to.The
IDS are preset in the plug-in as follows:

Final Cylindrical Map

Right Side

Left Side

Top Side

Bottom Side

Front Side

Back Side

For the pictures that were used earlier, we will planar map
these pictures on the left, right (for the side view) and the front for the
front view.Here is how the material
editor should have been set up.

Figure 11

Mapping the Photographs

We must now use the UVW Mapping modifiers to map the
pictures onto the head.For mapping the
first material ID (1), just use cylindrical mapping with a dummy texture for
now.This will be explained in a little
bit.Now map the 2 photographs by adding
UVW Mapping modifiers for each of the faces. In this example, the left, right
and front were planar mapped onto the object.

Figure 12

Creating a Single Texture Map

Make sure you have installed the unwrap.dlu plug-in in your
3D Studio MaxÒ
“plugins” directory.We will delve into
this tools source code a little later.For now select the Utilities panel (the hammer).Next select the “more..”
button.Then scroll down until you find
the utility named “Unwrap Object Texture” and then click “OK”.Most of the defaults are fine, except that
you do want to select the “Spline Blending” radio button.The differences between no spline blending
and spline blending can be seen in Figure 13.The algorithm for selecting the triangles to render is based on using
the normal of the triangle and doing a dot product with the direction of the
unit cube.This then selects the texture
map, which is most likely to contribute the “best” pixels to the triangle.There could have been some sort of simple
blending done, but there was a better solution.Figure 13

Normal
Based

Normal Based with Spline
Blending

This tool was quite a feat to write and hopefully you will
really get some use out of it.Peter
Watje wrote the original program and my thanks go out to him for his fine
work.The code was since modified and
texture mapping was added.Chris Hecker
wrote the original texture mapping code, but it was modified to fit into this
framework.The last part of the code is
the actual difficult part.It was very
hard and very frustrating to write. The code is based on a paper written by
Peter J. Burt and Edward H. Adelson entitled “A Multiresolution Spline with
Application to Image Mosiacs.The difficult part of the code was
decomposing the images into Gaussian and Laplacian Image Pyramids.The code uses memory quite heavily and the
plug-in will warn you that it can take a while to generate the images and then
merge them all back together.On a
Pentium III 500 MHZ, it takes about 20 seconds.The time to generate the map is acceptable given the results of the
blending.Save this image to the disk.

Putting it all together

Now that you have a single texture map, we can re-run the process
that was described at the beginning of the chapter.From this image we can generate the diffuse,
specular and bump map in the same way we did before.Before you export the file, you should remove
the UVW mapping coordinates for the front, left and right views, leaving the
cylindrical map.Now change the map type
to a normal bitmap and load in the image you had save before.You don’t even have to modify the UVW
coordinates, because the image was generated from the cylindrical map and they
should line up automatically for you.You can render the image in 3D Studio MaxÒ (See Figure 14)